diesel in a petrol mower - richy
(Ok so I know this is ment to be a car forum...)
I've been given a small 3.5hp petrol powered mower only a couple of years old. The gilfriend's dad gave it me after it cut out on him when he mistakenly filled it with diesel from a can. He said it ran for a couple of min, lost revs, then stalled. When it would'nt start after many atempts he realised his error. It would be helpfull for me to get it going because I've just moved into my first house and with the expense of everything don't realy want to be buying a new mower just yet.
Anyway, I drained the all diesel out, took the spark plug out, pulled the cord a few times and a black oily-diesel stuff came out the spark plug hole. I cleaned it up as much as I could by poking a rag into the hole with a screw-driver. I've also checked the plug still works in another mower, but the thing refuses to fire up at all. Any ideas or am I chasing a lost cause?
diesel in a petrol mower - Dynamic Dave
Suggest pouring petrol down the plug hole to flush out the remaining diesel/gunge, then drain the engine oil and refill. Might be worth also removing the carb and cleaning out as well.

diesel in a petrol mower - dieselhead
Don't recommend pouring petrol down the plug hole this is likely to flood the engine and wash away lubricant and scuff the cylinder when you start it up. Cranking with the plug removed will flush enough diesel out to allow the engine to start.

Remove and replace the carburettor float bowl to get all the diesel out then fill tank to maximum and keep cranking until it fires up. might have to remove the plug a couple of times between crankings to clean off any diesel oil before it fires.

Would be a good idea to change the oil if it's had diesel in.
diesel in a petrol mower - Sooty Tailpipes
Remove the spark plug, and as said, pull the starter a few times, pump the primer bulb 5 times, pull the starter, keep doing this, until you smell petrol vapours coming out the plug hole. Now heat the glow plug to operating temperature with a flame while holding it in the spanner, and then install, press the primer bulb 3-5 time and pull, it will hopefilly start, if not, maybe the carburettor has been permanently affected.
diesel in a petrol mower - Altea Ego
glow plug? it was a diesel mower then
diesel in a petrol mower - Sooty Tailpipes
Sorry, I meant spark plug, it's certainly a well used trick amongst people who use brushcutters, chainsaws and other 2 stroke implements, so I assume it would work on a four stroke - never needed to try it myself.
diesel in a petrol mower - Cliff Pope
Try a squirt of Easistart or similar - the ether-based stuff that will start anything. Either into the carb, or take the plug out and squirt straight into the cylinder and quickly replace the plug.
A stubborn engine sometimes starts more easily if you just pour boiling water over the inlet/carb duct - not down the inlet, obviously.
Once started it should be fine. I ran a mower for years on a 20% diesel mixture, the result of the usual carelessness at the pumps. It seemed a shame to waste 10 gallons of the stuff.
diesel in a petrol mower - dieselnut
Diesel tends to block the very small jets as it doesn't evaporate very well. As mowers only really need the smell of petrol to run you may have to blow out each jet & passage, but try just draining the float chamber first.
diesel in a petrol mower - psych
I did the same last year.... got a couple of cans in the garage muddled. I found just draining the tank, swilling it with petrol, and giving the mower a couple of pulls with the ignition disconnected cleared it. Smoked like nothing on earth for about five minutes, but run like a dream since. That said my mower is nearly 40 years old ........... are newer ones as robust??
diesel in a petrol mower - richy
Thanks for all your advice guys, if it eventualy stops raining by the weekend I shall put it to practice, will let you know how I get on.
Thanks again,
diesel in a petrol mower - stewart
More than five years after this request was posted, I had today, the situation where my wife filled mower with diesel. Through Google I found these replies. Problem sorted! I've now registered with Honest John.
diesel in a petrol mower - bathtub tom
>>Thanks for all your advice guys, if it eventualy stops raining by the weekend

Seems like it's been raining for five years!